Safety link tongs



c. E. oLsl-:N i-:T'AL 2,045,869

SAFETY LINK TONGS Filed Deo. 18, 1954 Carl E. lsen Joseph A. Peter.: on

INVI-ENKTORJ)` ATTORNEY.

'Patented June 30, 1936 tritt-9v PATENT OFFICE SAFETY LINK ToNGs Carl E. Olsen and Joseph A. Peterson, Houston, Tex.

Application December 18, 1934, Serial No. 758,001 s claims. (c1. :x1-'ssl 'This invention relates to tongs, and more particularly to the class of tongs that use chains and which are specially adapted for use in connectio-n with pipe. v

Among the objects of this invention are the attainment of maximum flexibility of the vchain parts and greater safety in their use.

The foregoing and other lobjects have been attained by means preferably interposed in the chain formation, which means is flexible allowing ready utilization with pipe members of varying diameter and having in combination therewith means which is rigid under al1 conditions of normal loading, and which yields in la predetermined manner under conditions of excess loading so as to avoid destruction lof the equipment, parting of the chain or possible injury to the operators.

Fig. v'1 is a plan view of a device incorporating the novel features `of this invention.

20 Fig. 2 is an enlarged plan view showing `some of the parts partially in section.

Fig. 3 is an elevation `of a `chain incorporating the features ofthis invention, a portion of the safety links being shown in section.

Fig. 4 'is a variation in the construction of the invention `as illustrated in Figs. A1 to 3.

Fig. v5 is 'a cross' section on the line 5--5 of Fig. 4.

This invention will be better understood when considering the drawing in lconnection with the following specication and appended claims:

In Fig. 1 the `invention Vis illustrated as applied to a 'form of tongs sometimes called a back-up tongs. The tongs are composed vessentially ol a handle I0, a flexible chain II, and a pipe grip or bit portion I2. These parts are 'shown in position with respect to a section of pipe I3. 'Interposed vin the flexible 'chain II is .a safety link 'I4 providing against vbreakage of the 'chain `Without destroying the chains normal flexibility.

In this particular embodiment the device includes 'a master vlink I5 embodying in combination certain features of flexibilityand having an enlarged en'd portion IB arranged to `cooperate with the handle I by means of the 'master link handle pin I'I"I. (This 'latter pin 'extends through suitable openings inthe handle 4and an vopening.

for the reception of a pin 2I whereby the masterv link is secured to the link element I4. Disposed between the openings I8 and 20 in the master link is a further opening 22 of such size and conguration as to insure the adaptation of the chain to pipe sections of different diameter, and to further provide necessary slack for the assembling of the tongs'in relation to the pipe. `understood that although the link I5 combines the functions of a master link and the features of the present invention, this arrangement is not byl way of limitation, but for the purpose of illus- Vtrating a preferred embodiment, as its right hand end may be so constructed as to cooperate with vanother prtion of chain l-I instead of with the g handle lII.

Link I4 is preferably substantially diamond shape, with two side wall portions 23 interconnec'ted by portions 24 of suit-able form to retain the linkin its normal shape and resist any tendencyof the ends 25 vand 26 to spread.

All of the pins used in the tongs with the pessi- 'bl-e kexception of the master pi-n I9 are preferably ofthe same diameter so that they may '-be readily interchanged. The pin 2-1 is vof the same diameter as theother pins but is arranged so as to v'shear through if an excessive load is applied to the apparatus. This is accomplished either by constructing it of y'different material from the re- -I mai-ning parts Iof the chain, or by making Ait with suitably reduced portions substantially in the plane'between the'coinponent parts ofthe links I4 and I5. Inthis rmanner breakage of the remaining parts of 4the ldevice is substantially precluded two elements. The renlarged Yopening 2.2 A.in link .I5 allows the flattentoipivotrabout the pointlll. A

.further interconnection between these .two .ele-

ments is -by means of alpin 30 which is of standard construction, as are .the .remaining pins 3| Aof the chain, and vwhich ,passes .through opening 422.

In operation the tongs are assembled with .respect to -the pipe, the nalposition being 'similar to 'that illustrated 'in Fig. 1. As long as the load applied `to the tongs does not 'exceed that for which they `are normally to be used, the parts remain in the relation illustrated. If, however, this load for any reason should approach the normal strength of the links II or the pins 3|, a shearing action will take place in the pin 2I at the points 32, where the pin is reduced in It is readily determined limited movement.

section. This reduced section is preferably arcuate in transverse section so that the point of actual shear will preferably occur midway of the reduced section portion. With this pin alone the chain would separate into at least two component parts and fly away from the pipe, possibly destroying additional equipment or injuring persons in the immediate vicinity. To avoid these conditions, a further connection between the links I4 and I5 is by means of a pin 3D and the enlarged'ope'ning 22. The enlarged opening allows the chain to spread or extend in the direc- Y tion of its length when the pin 2l is sheared' v while still maintaining a continuity of the chain construction per se. In this manner the immev diate excess load is dissipated through vthe l breakage of the pin 2| and the chain is maintained as a continuous member and prevented;

from separating into several parts.

A further variation of the construction de-v scribed is illustrated in Figs. 4 and 5 wherein the safety link is of such construction to be readily interposed at lsubstantially any pointin the chain, and is of such type as to be readily utilizable with respect to pipes otrelatively small diameter. In this variation the chain is composed of interchangeable links 4l and 42 interconnected by pins 43. Interposed between the two portions of the chain are the elements 44 and 45 comprising the safety link. The member 44 is substantially U-shaped in transverse `section having a plurality of openings arranged to receive the pins 45, v4l and 48. Pin 45 connects one end of the chain for example link 42 to the portion 44 of the safety link. Pin 4l interconnects parts 44 and 45 and is preferably olf construction similar to the pin 2|. Pin 48 is arranged to pass through an arcuate slot 49 in the link member 45, andis arranged so that the parts 44V and 45 pivotabout point 4l with a pre- Link 45 is connected to the opposite chain end bypin 55. Pins 43, 4S, 55 and 48 areinterchangeable andmay be substitutedV for the pin 4l if need should arise. A further detailed description of pin 41 is not believed necessary inasmuch as it preferably incorporates a plurality-of Vreduced section portions El as found at 32 irri-pin 2l. It is readily apparent that with pins 5S, 4l Vand 46 spacedl at uniform intervals corresponding to the pitch of the remaining links of the chain, that a very close and flexible arrangement is provided for cooperation with the pipe 40. Similarly in this construction if an excess load is applied tothe chain the pin 4'lwi1l shear through at 5| and the chain may become extended due to the ,shearing of the pivots at-4l, rbut theextension will be pre- `determined due to the cooperation oi pin 48 Iand slot 52 at one or both extremities similar to the slots 32 and 5! in which may be interposed a split ring 53 of such diameter that it will prevent the pin normally from being displaced but which will readily contract and allow the pin toV be ity of *saidVV linksV upon` destruction structible connection.

Y shearing or said first pivot.

removed if a sharp blow is applied to either end of the pin.

It is now clear that the chain may break at a predetermined point due to excess or abnormal loading in use, thus preventing the destruction of the links, but at the same time it is maintained as a continuous entity.

Although the invention has been described as applied to a particular embodiment for the purposes of illustration, various other modifications within the true spirit and scope of the invention are aimed to be covered by the hereto 'appended claims.

Vas a-portion of a chain, two pivots interconnecting said links, and means whereby one of said pivots is relatively fixed and the other allows relative movement between the links about the first pivot said first pivot being relatively weaker than said second pivot'.

2. AV safety linkage comprising a plurality of links, a plurality of pivots interconnecting a pair of adjacent links, one Vof said pivots beingthe more readily shearable of said pivots, another of said pivots loosely engaging one of 'said links to allow relative pivotal motion of said links about the rst pivot and arranged to maintain a different predetermined continuity of the linkage upon the shearing of the first named pivot.

3. A safety linkage comprising a plurality of links, a plurality of pivots interconnecting a pair oi adjacent links, one ofY said pivots being of reduced sectionY and the more readily shearable oi said pivots, another of said pivots loosely engaging one of said links to allow relative pivotal motion of said links about the first pivot and arranged to maintain a different predetermined continuity of the linkage upon the shearing of the first named pivot. 1

4. A chain safety linkage comprising in combination link elements interconnected and arranged to have predetermined pivotal movement, aY destructible pivotal connection between two of said elements, and means for maintaining the Ycontinuity otsaid linkage upon destruction of said destructible connection.

5. A safety linkageI including a plurality of interconnecting links, a destructible pivotal connection between two of said'links, and means normally limiting pivotal movement about said pivotal connection, and Vfor maintaining continuof said de- 6."A safety linkage comprising a pair of links and a plurality of spaceolpivots interconnecting said links, one of said pivots having a relatively close engagement with Vboth of said links to provide a relatively xed pivotal connection therebetween, said"pivt being the relatively more readily shearable and the vother of said pivots having Va relatively loose engagement with one Vsaid links to provide for relative pivotal motion of said links about'said nrst pivot, and for maintaining the continuity of said linkage upon CARL E. OLSEN.

`JOSEPH A. PETERSON. 

